import java.util.Scanner;

public class Three{
    static  int N=(int)1e4+10;
    static int[] sum=new int[N];
    static int[] f=new int[N];
    static int[] g=new int[N];

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n=in.nextInt();
        int x=0;
        for (int i = 0; i < n; i++) {
            x=in.nextInt();
            sum[x]+=x;
        }
        for (int i = 1; i < N; i++) {
            f[i]=g[i-1]+sum[i];
            g[i]=Math.max(g[i-1],f[i-1]);
        }
        System.out.println(Math.max(f[N-1],g[N-1]));
    }
}
